Black has been deprived of any counterplay.

Desperation in a difficult position.

White went on to win.

Restricting White's intended queenside advance,which could have become real after 1...Bxa3?1 2.Nxa3 , followed by Nc2, a2-a3 and b3-b4.

Speeding up the kingside play before White consolidates with Nd2-f3.

7.f4 runs into 7...g5 8.fxg5 Ng6 with a strong initiative.

Preparing ...h7-h5 with an attack. Thanks to his powerful knight, Black enjoys good compensation for the pawn.

In order to imprison Black's bishop just before he vacates the f8-square by ...Rfe8 or ...Rfc8.

From now White is basically a piece up and should just try to neutralize Black's temporary initiative.